When material including index tabs are xerographically copied, sometimes plain index sheets are used, and sometimes the index sheets are mounted with reinforcing at the high-wear index tabs area. When plain index sheets are used, there is normally no problem with copying, and relatively good toner adherence is present. However, without reinforcing, the tabs often wear out or are accidentally torn off. When an attempt is made to copy xerographically onto index sheets having polyester reinforced index areas, the toner often does not adhere to the glossy tabs, and there are often deletions or poor adhesion of the toner printing onto the tabs so that the printing is soon scraped away.
By way of background, it is noted that the conventional technique for adhering the polyester reinforcing to the index sheets, involves the use of a polyethylene coating on the polyester sheet material, and subsequent securing of the polyester reinforcing to the index tab of the index sheets, under heat and pressure, with the polyethylene coating bonding the polyester reinforcing tabs to the heavy paper index sheets at a temperature of about 210.degree. or 220.degree. F.
U.S. Pat. No. 5,135,261 involves forming index tab indicia separately on a label, and then securing the printed label onto the reinforced index tab by pressure sensitive adhesive. A coating on the label surface permits adhesion of xerographic toner to the label. In some cases, as an alternative, the index sheets may have file indicia pre-printed onto the index tab, and subsequently have the reinforcing applied over the pre-printed tabs. However, this method requires advance planning, and, flexibility in printing new indicia on the index tabs is lost.
Accordingly, a principal object of the present invention is to provide a coating directly on a reinforced index tab, which will not interfere with the securing of the polyester reinforcing to the index sheet, and which will be xerographic toner receptive, and where the resulting printing is resistant to abrasion.